[PATCH V5 2/7] mm: mlock: Add new mlock system call

From: Eric B Munson
Date: Fri Jul 24 2015 - 17:29:06 EST

With the refactored mlock code, introduce a new system call for mlock.
The new call will allow the user to specify what lock states are being
added. mlock2 is trivial at the moment, but a follow on patch will add
a new mlock state making it useful.

Signed-off-by: Eric B Munson <emunson@xxxxxxxxxx>
Cc: Michal Hocko <mhocko@xxxxxxx>
Cc: Vlastimil Babka <vbabka@xxxxxxx>
Cc: Heiko Carstens <heiko.carstens@xxxxxxxxxx>
Cc: Geert Uytterhoeven <geert@xxxxxxxxxxxxxx>
Cc: Catalin Marinas <catalin.marinas@xxxxxxx>
Cc: Stephen Rothwell <sfr@xxxxxxxxxxxxxxxx>
Cc: Guenter Roeck <linux@xxxxxxxxxxxx>
Cc: linux-alpha@xxxxxxxxxxxxxxx
Cc: linux-kernel@xxxxxxxxxxxxxxx
Cc: linux-arm-kernel@xxxxxxxxxxxxxxxxxxx
Cc: adi-buildroot-devel@xxxxxxxxxxxxxxxxxxxxx
Cc: linux-cris-kernel@xxxxxxxx
Cc: linux-ia64@xxxxxxxxxxxxxxx
Cc: linux-m68k@xxxxxxxxxxxxxxxxxxxx
Cc: linux-am33-list@xxxxxxxxxx
Cc: linux-parisc@xxxxxxxxxxxxxxx
Cc: linuxppc-dev@xxxxxxxxxxxxxxxx
Cc: linux-s390@xxxxxxxxxxxxxxx
Cc: linux-sh@xxxxxxxxxxxxxxx
Cc: sparclinux@xxxxxxxxxxxxxxx
Cc: linux-xtensa@xxxxxxxxxxxxxxxx
Cc: linux-api@xxxxxxxxxxxxxxx
Cc: linux-arch@xxxxxxxxxxxxxxx
Cc: linux-mm@xxxxxxxxx
---
Changes from V4:
* Drop all architectures except x86[_64] from this patch, MIPS is added
later in the series. All others will be left to their maintainers.

Changes from V3:
* Do a (hopefully) complete job of adding the new system calls
arch/alpha/include/uapi/asm/mman.h | 2 ++
arch/mips/include/uapi/asm/mman.h | 5 +++++
arch/parisc/include/uapi/asm/mman.h | 2 ++
arch/powerpc/include/uapi/asm/mman.h | 2 ++
arch/sparc/include/uapi/asm/mman.h | 2 ++
arch/tile/include/uapi/asm/mman.h | 5 +++++
arch/x86/entry/syscalls/syscall_32.tbl | 1 +
arch/x86/entry/syscalls/syscall_64.tbl | 1 +
arch/xtensa/include/uapi/asm/mman.h | 5 +++++
include/linux/syscalls.h | 2 ++
include/uapi/asm-generic/mman.h | 2 ++
include/uapi/asm-generic/unistd.h | 4 +++-
kernel/sys_ni.c | 1 +
mm/mlock.c | 9 +++++++++
14 files changed, 42 insertions(+), 1 deletion(-)

diff --git a/arch/alpha/include/uapi/asm/mman.h b/arch/alpha/include/uapi/asm/mman.h
index 0086b47..ec72436 100644
--- a/arch/alpha/include/uapi/asm/mman.h
+++ b/arch/alpha/include/uapi/asm/mman.h
@@ -38,6 +38,8 @@
#define MCL_CURRENT 8192 /* lock all currently mapped pages */
#define MCL_FUTURE 16384 /* lock all additions to address space */

+#define MLOCK_LOCKED 0x01 /* Lock and populate the specified range */
+
#define MADV_NORMAL 0 /* no further special treatment */
#define MADV_RANDOM 1 /* expect random page references */
#define MADV_SEQUENTIAL 2 /* expect sequential page references */
diff --git a/arch/mips/include/uapi/asm/mman.h b/arch/mips/include/uapi/asm/mman.h
index cfcb876..67c1cdf 100644
--- a/arch/mips/include/uapi/asm/mman.h
+++ b/arch/mips/include/uapi/asm/mman.h
@@ -62,6 +62,11 @@
#define MCL_CURRENT 1 /* lock all current mappings */
#define MCL_FUTURE 2 /* lock all future mappings */

+/*
+ * Flags for mlock
+ */
+#define MLOCK_LOCKED 0x01 /* Lock and populate the specified range */
+
#define MADV_NORMAL 0 /* no further special treatment */
#define MADV_RANDOM 1 /* expect random page references */
#define MADV_SEQUENTIAL 2 /* expect sequential page references */
diff --git a/arch/parisc/include/uapi/asm/mman.h b/arch/parisc/include/uapi/asm/mman.h
index 294d251..daab994 100644
--- a/arch/parisc/include/uapi/asm/mman.h
+++ b/arch/parisc/include/uapi/asm/mman.h
@@ -32,6 +32,8 @@
#define MCL_CURRENT 1 /* lock all current mappings */
#define MCL_FUTURE 2 /* lock all future mappings */

+#define MLOCK_LOCKED 0x01 /* Lock and populate the specified range */
+
#define MADV_NORMAL 0 /* no further special treatment */
#define MADV_RANDOM 1 /* expect random page references */
#define MADV_SEQUENTIAL 2 /* expect sequential page references */
diff --git a/arch/powerpc/include/uapi/asm/mman.h b/arch/powerpc/include/uapi/asm/mman.h
index 6ea26df..189e85f 100644
--- a/arch/powerpc/include/uapi/asm/mman.h
+++ b/arch/powerpc/include/uapi/asm/mman.h
@@ -23,6 +23,8 @@
#define MCL_CURRENT 0x2000 /* lock all currently mapped pages */
#define MCL_FUTURE 0x4000 /* lock all additions to address space */

+#define MLOCK_LOCKED 0x01 /* Lock and populate the specified range */
+
#define MAP_POPULATE 0x8000 /* populate (prefault) pagetables */
#define MAP_NONBLOCK 0x10000 /* do not block on IO */
#define MAP_STACK 0x20000 /* give out an address that is best suited for process/thread stacks */
diff --git a/arch/sparc/include/uapi/asm/mman.h b/arch/sparc/include/uapi/asm/mman.h
index 0b14df3..13d51be 100644
--- a/arch/sparc/include/uapi/asm/mman.h
+++ b/arch/sparc/include/uapi/asm/mman.h
@@ -18,6 +18,8 @@
#define MCL_CURRENT 0x2000 /* lock all currently mapped pages */
#define MCL_FUTURE 0x4000 /* lock all additions to address space */

+#define MLOCK_LOCKED 0x01 /* Lock and populate the specified range */
+
#define MAP_POPULATE 0x8000 /* populate (prefault) pagetables */
#define MAP_NONBLOCK 0x10000 /* do not block on IO */
#define MAP_STACK 0x20000 /* give out an address that is best suited for process/thread stacks */
diff --git a/arch/tile/include/uapi/asm/mman.h b/arch/tile/include/uapi/asm/mman.h
index 81b8fc3..f69ce48 100644
--- a/arch/tile/include/uapi/asm/mman.h
+++ b/arch/tile/include/uapi/asm/mman.h
@@ -37,5 +37,10 @@
#define MCL_CURRENT 1 /* lock all current mappings */
#define MCL_FUTURE 2 /* lock all future mappings */

+/*
+ * Flags for mlock
+ */
+#define MLOCK_LOCKED 0x01 /* Lock and populate the specified range */
+

#endif /* _ASM_TILE_MMAN_H */
diff --git a/arch/x86/entry/syscalls/syscall_32.tbl b/arch/x86/entry/syscalls/syscall_32.tbl
index ef8187f..839d5df 100644
--- a/arch/x86/entry/syscalls/syscall_32.tbl
+++ b/arch/x86/entry/syscalls/syscall_32.tbl
@@ -365,3 +365,4 @@
356 i386 memfd_create sys_memfd_create
357 i386 bpf sys_bpf
358 i386 execveat sys_execveat stub32_execveat
+359 i386 mlock2 sys_mlock2
diff --git a/arch/x86/entry/syscalls/syscall_64.tbl b/arch/x86/entry/syscalls/syscall_64.tbl
index 9ef32d5..ad36769 100644
--- a/arch/x86/entry/syscalls/syscall_64.tbl
+++ b/arch/x86/entry/syscalls/syscall_64.tbl
@@ -329,6 +329,7 @@
320 common kexec_file_load sys_kexec_file_load
321 common bpf sys_bpf
322 64 execveat stub_execveat
+323 common mlock2 sys_mlock2

#
# x32-specific system call numbers start at 512 to avoid cache impact
diff --git a/arch/xtensa/include/uapi/asm/mman.h b/arch/xtensa/include/uapi/asm/mman.h
index 201aec0..11f354f 100644
--- a/arch/xtensa/include/uapi/asm/mman.h
+++ b/arch/xtensa/include/uapi/asm/mman.h
@@ -75,6 +75,11 @@
#define MCL_CURRENT 1 /* lock all current mappings */
#define MCL_FUTURE 2 /* lock all future mappings */

+/*
+ * Flags for mlock
+ */
+#define MLOCK_LOCKED 0x01 /* Lock and populate the specified range */
+
#define MADV_NORMAL 0 /* no further special treatment */
#define MADV_RANDOM 1 /* expect random page references */
#define MADV_SEQUENTIAL 2 /* expect sequential page references */
diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h
index b45c45b..56a3d59 100644
--- a/include/linux/syscalls.h
+++ b/include/linux/syscalls.h
@@ -884,4 +884,6 @@ asmlinkage long sys_execveat(int dfd, const char __user *filename,
const char __user *const __user *argv,
const char __user *const __user *envp, int flags);

+asmlinkage long sys_mlock2(unsigned long start, size_t len, int flags);
+
#endif
diff --git a/include/uapi/asm-generic/mman.h b/include/uapi/asm-generic/mman.h
index e9fe6fd..242436b 100644
--- a/include/uapi/asm-generic/mman.h
+++ b/include/uapi/asm-generic/mman.h
@@ -18,4 +18,6 @@
#define MCL_CURRENT 1 /* lock all current mappings */
#define MCL_FUTURE 2 /* lock all future mappings */

+#define MLOCK_LOCKED 0x01 /* Lock and populate the specified range */
+
#endif /* __ASM_GENERIC_MMAN_H */
diff --git a/include/uapi/asm-generic/unistd.h b/include/uapi/asm-generic/unistd.h
index e016bd9..14a6013 100644
--- a/include/uapi/asm-generic/unistd.h
+++ b/include/uapi/asm-generic/unistd.h
@@ -709,9 +709,11 @@ __SYSCALL(__NR_memfd_create, sys_memfd_create)
__SYSCALL(__NR_bpf, sys_bpf)
#define __NR_execveat 281
__SC_COMP(__NR_execveat, sys_execveat, compat_sys_execveat)
+#define __NR_mlock2 282
+__SYSCALL(__NR_mlock2, sys_mlock2)

#undef __NR_syscalls
-#define __NR_syscalls 282
+#define __NR_syscalls 283

/*
* All syscalls below here should go away really,
diff --git a/kernel/sys_ni.c b/kernel/sys_ni.c
index 7995ef5..4818b71 100644
--- a/kernel/sys_ni.c
+++ b/kernel/sys_ni.c
@@ -193,6 +193,7 @@ cond_syscall(sys_mlock);
cond_syscall(sys_munlock);
cond_syscall(sys_mlockall);
cond_syscall(sys_munlockall);
+cond_syscall(sys_mlock2);
cond_syscall(sys_mincore);
cond_syscall(sys_madvise);
cond_syscall(sys_mremap);
diff --git a/mm/mlock.c b/mm/mlock.c
index 1585cca..c9c6a0f 100644
--- a/mm/mlock.c
+++ b/mm/mlock.c
@@ -642,6 +642,15 @@ SYSCALL_DEFINE2(mlock, unsigned long, start, size_t, len)
return do_mlock(start, len, VM_LOCKED);
}

+SYSCALL_DEFINE3(mlock2, unsigned long, start, size_t, len, int, flags)
+{
+ vm_flags_t vm_flags = VM_LOCKED;
+ if (!flags || (flags & ~(MLOCK_LOCKED)))
+ return -EINVAL;
+
+ return do_mlock(start, len, vm_flags);
+}
+
SYSCALL_DEFINE2(munlock, unsigned long, start, size_t, len)
{
int ret;
--
1.9.1

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